The focus of the study is on the process of peasant migration and population redistribution in five urban-rural levels (dispersed, village, simple urban, complex urban, and metropolitan) in a developing country. A follow-up case study in depth of out-migrants from a small village in rural Argentina provides the instance to analyze the causes of out-migration and effects of migration upon origin and destination communities, with special attention to changes in attitudes and behavior and to problems of assimilation into new environments. This out- migration process among farmers of a German cultural background (Volga- Deutsch) living in a plains setting closely parallels the rural depopulation of the midwestern United States between World War I and World War II. Two time frames of in-depth study have been completed that contrast the 1966-67 period, while the village was still culturally isolated and relatively untouched by the modern world, and 1973-74, after the impact of modernization and mechanization had begun to transform the village and destination areas of many of the out-migrants. This study also provides a complete history of a migrant population from rural origins to assimilation into new environments, and provides an instance for documenting the entire migration process for this population over a fifty year period. The three major goals of this research are: (1) to assess the effect of the interrelationship of psychosocial, spatial, environmental, economic and other factors on the migration of different social classes and behavioral subgroups; (2) to relate attitudes, decisions, and behavior relating to migration of the various population subgroups to the successfulness of assimilation in new environments; and (3) to explore the general implications of population redistribution and migrant assimilation for rural and urban development.